The leachability and potential environmental risks of uranium (U) and thorium (Th) in aquifer sediments from a recent uranium minesite of northern Guangdong Province, China were investigated as part of ongoing environmental investigations. Data for the non-mineralogical portion of U, Th and of additional major elements(Mn, Fe, Ca, Mg, Na, Al and K) using a 0.5 mol/L HCl partial leach and inductively coupled plasma optical emission spectrometry (ICP-OES) were presented for the contaminated sediments and a background sediment. The contaminated sediments reported leachable contents of U between 22.85 and 2700 mu g/g and those of Th between 4.800 and 102.1 mu g/g, which exceed by a few to several hundred times the respective content found in the background. Generally, the leachable U and Th contents in the stream sediments decrease with distance from the potential contamination sources. A special case is the runoff gathering reservoir located around 1 km downstream of the U mine-site, representing the most severe metal contamination hotspot within the alpine watershed, where the highest leachable content of U and Th in the inlet sediment was observed. The highest leachability of U (68.6%) and Th (44.8%) was observed in this sediment as well, indicating a high potential of bioaccumulation and bioconcentration of U and Th under changing geochemical conditions. Correlations analysis indicates that the dilute HCl leachable fraction of U and Th bound in the sediments are strongly dependent on anthropogenic inputs from the U mining/milling activities, and Ca salts are the main vectors. (C) 2016 Elsevier B.V. All rights reserved. Publication name | JOURNAL OF GEOCHEMICAL EXPLORATION, 176 85-90; SI 10.1016/j.gexplo.2016.01.008 MAY 2017 | Author(s) | Wang, Jin; Liu, Juan; Li, Hongchun; Chen, Yongheng; Xiao, Tangfu; Song, Gang; Chen, Diyun; Wang, Chunlin | Corresponding author(s) | WANG Jin; CHEN Yongheng wangjin200726@hotmail.com; chenyong_heng@163.com - Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources, Guangzhou University, Guangzhou 510006, China - Innovation Center and Key Laboratory of Waters Safety & Protection in the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China | Author(s) from IGCAS | XIAO Tangfu | View here for the details
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